1. Field of the Invention
The present invention relates to a ball chair, and more particularly to a ball chair having multiple strengthening blocks at joints of the ball chair to avoid the ball chair cracking at the joints.
2. Description of Related Art
A conventional ball chair is composed of a chair and a ball-shaped cushion. The chair has a seat plate with a top face and a bottom face. A partly-spherical passage is defined in the top face of the seat plate to receive a lower portion of the ball-shaped cushion inside. At least three legs are attached to the bottom face of the seat plate to support the ball chair. By placing the ball-shaped cushion in the partly-spherical passage of the chair, a ball chair is achieved. However, when a user sits in the ball chair, the ball-shaped cushion is pressed to deform forward and then falls out of the partly-spherical passage such that the user easily falls from the ball chair. Additionally, when the ball chair is bumped or vibrated, the ball-shaped cushion rebounds and easily springs out of the partly-spherical passage. Therefore, a backrest or a guard securing means is attached on the top face of the seat plate to hold the ball-cushion in place. However, with regard to the seat plate, it is usually made of plastic by blow molding and thus is a hollow body that is easily broken, especially at joints between the seat plate and the legs. Therefore, the ball chair is not safe and not stable for the user.
Additionally, the ball chair has a constant height and can not satisfy tall people so that the ball chair is limited to be only suitable for people of a certain height.
The present invention has arisen to mitigate or obviate the disadvantages of the conventional ball chair.
The main objective of the present invention is to provide a ball chair with strengthening blocks that avoid a seat cracking at joints where multiple legs are attached, whereby, the ball chair is safe and steady.
Another main objective of the present invention is to provide a ball chair further having a detachable post attached between the seat and the leg to adjust the height of the ball chair.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.